Method of rolling titanium and other rods

ABSTRACT

Titanium and similar rods reduced in diameter by heating to a required temperature and then continuously passing a rod through roll stands to progressively reduce its area without intervening reheating being necessary. The roll stands change the shape of the rod alternately between a round shape and a flat shape, a pair of opposed flat sides of each flat configuration merging smoothly into a pair of opposed rounded sides of relatively large radius of curvature, thereby avoiding the formation of sharp corners as a result of each flattening operation.

United States Patent I 72] Inventor Bend] 0. M

u Ranch nu Ru. i:- 83. l6222 Monterey Lure, Huntington Beach, Calif. 92647 [2| 1 Appl. No. 811,301 [22] Filed Mar. 28. I969 [45] Patented Aug. 24,197!

I 54] METHOD OF ROLLING TITANIUM AND OTHER RODS 14 China, 2 Drewlng Fl (52] U.S.Cl 72/234 [51] Int. B2lh3l/08 [50] Field oISeench 72/234, 235, 226, 366, 200 [$6] Relerenees Cited UNITED STATES PATENTS 1,883,205 l0/l932 Whitehead .7 72/235 2,l40,4l4 l2/l938 Brownstein 72/235 2,400,690 5/1946 Fisk 72/235 3,498,097 3/1970 Mishuku 72/234 Primary Examiner-Milton S. Mehr Attorney Bernard Kriegel METHOD OF ROLLING TITANIUM AND OTHER RODS The present invention relates to a method of reducing the diameters of rods, and more particularly to the production of small-decimal-size rods of titanium and similar exotic metals.

The reduction of the diameter of titanium rods to a substantially small diameter has been difiicult of accomplishment, taking substantial time, having a high operating cost, and producing a relatively low yield. In prior methods, the initial rod of round cross section was first annealed, its end then pointed by swagging, the rod being descaled in four steps, including application of a caustic, a rinse, application of an acid, and another rinse, a coating being applied to the rod so that the drawing lubricant will adhere thereto, the coating being dried, and the dried coated rod then being drawn on a bull block. Assuming that the initial rod diameter was about 0.440 inches, and it was desired to reduce its diameter to 0. I32 inches, the above six main steps had to be repeated approximately 10 times, as l draws were required before reaching the desired size of 0.132 inches in diameter. Accordingly, a total of 60 steps were required.

Attempts at rolling titanium rods to a smaller diameter have been unsuccessful. Such prior attempts included the passing of the rods through a rolling mill to flatten it, but such flattening produced rather sharp comers which cooled to an undesirable low temperature (the starting temperature being about l,750 F.). The flattened wire was then turned 90 and passed through another set of rolls, which elongated it and produced a generally square shape, but here again the comers lost too much heat. The square shaped rod was then turned 90 and passed through another set of rolls, which elongated it further and produced another flat shape having relatively sharp corners. The foregoing steps were repeated to progressively reduce the area of the rod until the desired final diameter was achieved. During each pass through a roll stand, the relatively sharp corners that resulted were too low in temperature to secure a proper rolling action, the rod of a progressively smaller cross-sectional area being defective. Accordingly, it has been impossible heretofore to continuously roll titanium rods from a larger diameter to a desired smaller diameter, unless the rod is reheated after each pass, which is a costly and time consuming operation.

The present method provides finished and semifinished rods of a reduced diameter in a rapid and economical manner. It is only necessary to heat the rod to the required initial temperature and then pass it through successive roll stands to reduce its diameter, the production of corners and sharp edges being eliminated. The rod passes alternately between rolls that flatten it from a round shape to a shape in which a pair of opposed, substantially flat sides merge smoothly into opposed rounded sides of relatively large radius of curvature. When the rod passes through the rolls that produce the final round shape desired, its temperature is still sufl'iciently high for the production of a proper rolling action thereon, resulting in a rod that is free from defects. Where the prior drawing process involved a .total of 60 steps for producing the final diameter, the present method accomplishes the same result in four steps, and possibly three. In general, applicant's method may involve an initial descaling step, but such step may not be necessary.

After the final round shape is obtained, if a further reduction in diameter is required, the temperature of the rod is again increased, the rolls that formerly produced the round shape having been changed to produce round shapes of progressively smaller diameter; whereas, the sets of rolls that perform the flattening operation need merely be adjusted to provide the required flat width across the rod. Not only are much fewer steps required, but the operation is many times faster. As an example, with the prior art drawing process, the speed of operation is approximately 28 feet per minute; whereas, in the process of the present invention, the speed of operation for reducing the rod diameter from about 0.440 inches to 0.132 inches is about 300 feet per minute, or almost eight and one-half times faster.

A further advantage of the present invention is that the wear of the rolls is considerably reduced, since the reduction in area in the rod passing through each mill stand is much less than in prior methods. Such reduction in wear on the rollers eliminates downtime. In addition, applicant '5 method permits the rod to be rolled at a lesser temperature, without fear of causing mechanical defects in the final product. In addition, less scaling on the rod is produced, resulting in a better final rod surface.

This invention possesses many other advantages and has other purposes which may be made more clearly apparent from a consideration of a method embodying the invention.

This method is shown and described in the present specification in connection with the drawings accompanying and constituting a part thereof. Such drawings and method will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense.

Referring to the drawings:

FIG. 1 is a diagrammatic view of a l0-stand rolling mill used in reducing the diameter of a rod; and

HO. 2 is a diagrammatic view illustrating the cross-sectional shapes of the rod produced as it moves progressively through the roll stands.

By virtue of the present invention, a continued rolling and reduction in area of a round titanium rod 101, or rod of any other metal, is accomplished. Assuming the rod to be titanium and of round cross section, it is heated to about l,750 F. and is then passed between the rollers A of a roll stand 1 that effect its flattening to a predetermined extent and also a reduction in its cross-sectional area. The opposed rollers A of the roll stand are separated the required distance, such rollers being of cylindrical form. The fiat sides 110 of the rod 100 are generally parallel to each other; whereas, the other pair of opposed sides llb are of rounded convex configuration, their radius of curvature being relatively large, the curved sides 1 lb merging smoothly into the flattened sides 110. This flattened rod then passes between the opposed rollers B of mill stand 2, these rollers being shaped to produce a circular cross section 10b in the rod, the rollers exerting a force in the direction of the arrows 50 and further reducing the cross-sectional area. The rod then passes between the cylindrical rollers C of mill stand 3, which again flatten the rod and reduces its cross-sectional area, the opposed flat sides 12a of the rod 10c merging smoothly into the opposed rounded sides 12b of the rod, the rounded sides having a relatively large radius of curvature. The rod 10c then passes between the rollers D of the next mill 4, which then shape it to a round cross section 10d of a still lesser cross-sectional area, from where the rod passes successively between the rollers E, F, G, H, J, K of mills 5, 6, '7, 8, 9 and I0, the rod being progressively reduced in cross-sectional area and its shape alternating between the flattened shape We, 10g, l0j with rounded opposed sides 13b, 14b, 15b and flat opposed sides l3a, 14a, 15a, and a round cross section 10], 10h, 10k, until the final diameter is achieved. As the round rod 10k leaves the final mill 10, it is found that its temperature has been reduced to only about l,450 F., which is still sufficiently high for producing a proper rolling action on the titanium rod, and that such rod is free from defects.

In the specific example described above, the mill may have 10 roll stands, the rolls of each stand being disposed at a 45 angle to the horizontal, and with the rolls of successive mills disposed at to each other. Mills 1, 3, 5, 7 and 9 will flatten the rod or wire while elongating it; whereas, mills 2, 4, 6, 8 and 10 will produce the round shape while elongating the rod. A relatively gradual reduction in cross-sectional area is produced, since great reductions cannot be secured properly on titanium rods. In each of mills l, 3, 5, 7 and 9, the opposed flattened sides merge smoothly into the opposed rounded sides, which have a comparatively large radius of curvature. The linear feed of the rod through the successive mills increases as its cross-sectional area is decreased, the speed of the rollers in each mill progressively increasing as the rod elongates. Although l-roll stands have been described above, as many can be used as is required to efiect the desired reduction in diameter.

ln HO. 2 are disclosed the cross sections of a typical rod as it is passing through the successive roll stands, beginning with the round cross section and alternating between the round and oval or flattened cross sections. it is found that the cross-sectional area of the oval should preferably bear a certain relation to the cross-sectional area of the rod that is next formed from such oval shape. The width or major diameter 60 of the oval should be about 1.5 times the diameter of the next succeeding round shape; whereas, the thickness or minor dimension 61 of the oval should be 0.95 times the diameter of the circular cross section resulting from the oval and produced in the next mill stand. it is also found that titanium, and other exotic metals, of small diameter can be successively rolled if the reduction in area achieved between each roll stand is about 13 to percent. This is borne out from actual reduction of titanium rods from an initial diameter of 0.437 inches to a final diameter of 0.2l8 inches. The following is the successive round diameter and oval shape indication given in effecting the reduction in the above example:

If desired, additional mill stands could be used or the distance between the cylindrical rollers of each of the oddnumber mill stands changed, and rollers substituted for the even-number mill stands, to progressively further reduce the diameter, shape and area of the rod as it passes between the roll stands, as follows:

Mill Number Rod Diameter or Shape Area I l Oval 0.0325

l2 0.190 0.0283 [3 Oval 0.0246

15 Oval 0.0]86

11 Oval 0.0l4l

ll 0.125 0.0l23

At each station where the oval or flattened shape is formed, the ratio between the width 60 of the oval will be about l.5 times the diameter of the round cross section formed in the next succeeding mill, and the thickness 61 will be about 0.95 times such diameter. Moreover, the radius of curvature of the curved sides llb, 12b, etcv of the oval shape will be about onehalf the thickness of the oval, actually being slightly less than one-half of such thickness.

After the rod has been reduced in size to its final diameter, it can be either coiled or retained in rolled lengths. Such rolled lengths can then be annealed, straightened and centerless ground to produce the desired finished product.

It is apparent that a simple method has been devised of producing small-decimal-size rods of various types of metal in an expeditious manner and with a very high yield and low operating cost. A high percentage of satisfactory rods is obtained, for example, 70 to percent, the finished rods being rolled to a close tolerance and being of uniform section. Tearing and cracking of the rods is virtually eliminated through use of the rolling method above described.

I claim:

1. The method of reducing the diameter of a round rod comprising heating the rod to elevate its temperature to a desired value, passing said heated rod between successive sets of opposed rollers to progressively decrease the cross-sectional area of the rod and shape the rod alternately between round and oval cross-sectional configurations, each of said oval configurations having opposed flattened generally parallel sides and opposed convexly curved sides merging smoothly into said flattened sides.

2. The method as defined in claim 1, the radius of curvature of said convexly curved sides being about one-half the thickness of said rod measured across said flattened sides.

3. The method as defined in claim 1, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod.

4. The method as defined in claim 1, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod, the radius of curvature of said convexly curved sides of each of said ovals being about onehalf the thickness of said rod across said flattened sides.

5. The method as defined in claim I, wherein each reduction in cross-sectional area is about l3 to l5 percent.

6. The method as defined in claim I, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod, each reduction in cross-sectional area being about 13 to 15 percent.

7. The method as defined in claim 1, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod, the radius of curvature of said convexly curved sides of each of said ovals being about one half the thickness of said rod across said flattened sides, each reduction in cross-sectional area being about 13 to l5 percent.

8. The method as defined in claim 1, the rollers of successive sets being disposed at to each other the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween.

9. The method as defined in claim 1, the rollers of successive sets being disposed at 90 to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween, the radius ,of curvature of said convexly curved sides being about one-half the thickness of said rod measured across said flattened sides.

10. The method as defined in claim I, the rollers of successive sets being disposed at 90 to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configura tion, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween,

the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod.

11. The method of reducing the diameter of a round rod comprising heating the rod to elevate its temperature to a desired value, passing said heated rod between successive sets of opposed rollers to progressively decrease the cross-sectional area of the rod and shape the rod alternately between round and oval crosssectional configurations, each of said oval configurations having opposed flattened sides and opposed convexly curved sides merging smoothly into said flattened sides, the rollers of successive sets being disposed at 90 to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween, the radius of curvature of said convexly curved sides of each of said ovals being about onehalf the thickness of said rod across said flattened sides.

12. The method of reducing the diameter of a round rod comprising heating the rod to elevate its temperature to a desired value, passing said heated rod between successive sets of opposed rollers to progressively decrease the cross-sectional area of the rod and shape the rod alternately between round and oval cross-sectional configurations, each of said oval configurations having opposed flattened sides and opposed convexly curved sides merging smoothly into said flattened sides, the rollers of successive sets being disposed at to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween, wherein each reduction in cross-sectional area is about 13 to 15 percent.

13. The method as defined in claim 12, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod.

14. The method as defined in claim 12, the radius of curvature of said convexly curved sides being about one-half the thickness of said rod measured across said flattened sides. 

2. The method as defined in claim 1, the radius of curvature of said convexly curved sides being about one-half the thickness of said rod measured across said flattened sides.
 3. The method as defined in claim 1, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod.
 4. The method as defined in claim 1, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod, the radius of curvature of said convexly curved sides of each of said ovals being about one-half the thickness of said rod across said flattened sides.
 5. The method as defined in claim 1, wherein each reduction in cross-sectional area is about 13 to 15 percent.
 6. The method as defined in claim 1, the major dimension of each of said ovals being about one and one-half times the diaMeter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod, each reduction in cross-sectional area being about 13 to 15 percent.
 7. The method as defined in claim 1, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod, the radius of curvature of said convexly curved sides of each of said ovals being about one-half the thickness of said rod across said flattened sides, each reduction in cross-sectional area being about 13 to 15 percent.
 8. The method as defined in claim 1, the rollers of successive sets being disposed at 90* to each other the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween.
 9. The method as defined in claim 1, the rollers of successive sets being disposed at 90* to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween, the radius of curvature of said convexly curved sides being about one-half the thickness of said rod measured across said flattened sides.
 10. The method as defined in claim 1, the rollers of successive sets being disposed at 90* to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod.
 11. The method of reducing the diameter of a round rod comprising heating the rod to elevate its temperature to a desired value, passing said heated rod between successive sets of opposed rollers to progressively decrease the cross-sectional area of the rod and shape the rod alternately between round and oval cross-sectional configurations, each of said oval configurations having opposed flattened sides and opposed convexly curved sides merging smoothly into said flattened sides, the rollers of successive sets being disposed at 90* to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween, the radius of curvature of said convexly curved sides of each of said ovals being about one-half the thickness of said rod across said flattened sides.
 12. The method of reducing the diameter of a round rod comprising heating the rod to elevate its temperature to a desired value, passing said heated rod between successive sets of opposed rollers to progressively decrease the cross-sectional area of the rod and shape the rod alternately between round and oval cross-sectional configurations, each of said oval configurations having opposed flattened sides and opposed convexly curved sides merging smoothly into said flattened sides, the rollers of successive sets being disposed at 90* to each other, the sets of rollers alternating between opposed cylindrical rollers to flatten the rod and produce the oval configuration and opposed peripherally grooved rollers to produce the round configuration, each set of said grooved rollers acting upon the opposed convexly curved sides of said oval rod passing therebetween, wherein each reduction in cross-sectional area is about 13 to 15 percent.
 13. the method as defined in claim 12, the major dimension of each of said ovals being about one and one-half times the diameter of the next succeeding round configuration of said rod and the thickness of said rod across said flattened sides being about 0.95 times the diameter of the next succeeding round configuration of said rod.
 14. The method as defined in claim 12, the radius of curvature of said convexly curved sides being about one-half the thickness of said rod measured across said flattened sides. 